In a conventional system for driving a winch or other gear driven device a gear set is engaged to drive the winch and a number of disengagement devices are known to disengage the gear set. In one such disengagement device, the ring gear of the gear set is released from driving the other gears and is allowed to turn freely with the rest of the gear set.
In this known device, a pin is used to secure the ring gear in place. This allows the other gears to drive against the ring gear and produce the necessary torque to drive the gear set. To disengage the gear set, the ring gear is allowed to turn freely with the rest of the gear set by pulling the pin out of engagement with the ring gear. The pin is normally activated by a handle attached to the opposite end of the pin that is engaged with the ring gear. The pin is supported for axial travel in a housing between the engagement and disengagement positions. When the handle is actuated, the pin is pulled to the disengagement position and the ring gear is set free.
Sometimes a fluid is used in place of the handle to disengage the ring gear. In this case, the housing for the handle is replaced with a different housing that allows the fluid to activate the pin, in the same manner as the handle, allowing the pin to slide axially back and forth between the engagement and disengagement positions. It is also known to attach a cylinder externally on the housing of the winch to achieve the same effect. When the fluid is supplied to the cylinder, it pulls the pin to the disengagement position, which in turn releases the ring gear to turn freely with the rest of the gears.
In both cases, when the handle or fluid is released, the pin is forced back to the engagement position by a spring acting on the pin.